The present invention relates generally to a cross-bar socket wrench having particular utility for use in applying and removing vehicle lug nuts during wheel mounting and wheel removal operations. The cross-bar socket wrench of the present invention has features which better and more expeditiously perform the operation, with the configuration of the device providing for articulation of the cross-bars from a closed or retracted disposition to a highly advantageous extended working disposition.
In the past, cross-bar wrenches have been well known and commonly used by vehicle operators and mechanics for loosening and tightening lug nuts during tire changing procedures. These cross-bar socket wrenches are desirable because they provide for the delivery of substantial torque to the nut, thereby enabling removal of those nuts which may have been inadvertently over-tightened, or which may have become frozen to the studs through corrosion. In either event, the cross-bar socket wrenches of the present invention enable the vehicle operator to loosen the lug nuts for removal and subsequent remounting of a wheel/tire to the vehicle. The term xe2x80x9clug nutsxe2x80x9d as used herein is utilized in a comprehensive sense, and thus includes corresponding structure such as lug bolts.
In order to provide for a compact structure, it is desirable to have the cross-bars pivotally coupled to the body of the wrench so that they may be articulated between a retracted disposition during storage, and an extended disposition during use. Thus, the wrench may be conveniently stowed within a pouch in the trunk of a vehicle, and quickly converted to its working disposition whenever needed.
In order to provide for a safe working environment, it is desirable that the hands of the user be positioned away from the socket tip while the wrench is being manipulated. However, the mere extension of length for the shaft forming the body of the wrench simply increases the size of the device, rendering it less compact. Furthermore, when the length of the shaft is increased, it may become necessary to increase the cross-sectional diameter in order to withstand the effects of the application of high torque. The features of the present invention accommodate articulation of the individual cross-bars so that a greater effective working length for the shaft is achieved, while at the same time providing for compact design. These features will be set forth in greater detail hereinbelow.
In accordance with the present invention, a cross-bar socket wrench is provided which includes a body member consisting of an elongated shaft with a rotatable gripping handle at one end and a socket-engaging tip at the opposed end. A torque bar retaining driving hub is secured to the shaft generally midway between the opposed ends, and a pair of torque bars are in turn coupled to the driving hub and arranged for pivotal rotation between an inwardly retracted storage disposition and a radially extended working disposition. The gripping handle comprises sleeve means which are freely rotatable about the shaft, for accommodating controlled rotation of the wrench body relative to the gripping handle. The rotatable sleeve permits free rotation of the wrench body, with the rotational inertia of the tool, as enhanced by the mass of the hub, being utilized to continue to drive the lug nuts. The driving hub is fast upon the elongated shaft, with the hub including a pair of radially outwardly disposed bar receiving pockets for pivotal articulation of the torque-applying bars. The proximal ends of the bars are pivotally coupled to the hub and adapted for rotation about pivot pins spanning each pocket, and thereby control and guide the pivotal motion of the bars relative to the shaft. In order to provide for greater effective shaft length between the hub and the socket-engaging tip, the configuration of the bar receiving pockets is such that the bars rotate from a retracted disposition substantially parallel with the elongated shaft to an extended working disposition at an oblique angle of at least about 95xc2x0 relative to the axis of the shaft.
It is a further feature of the invention to utilize torque bars which are solid from end to end, and are not cut-away to form coupling tangs or coupling forks. The pockets formed in the driving hub and into which the cross-bars are fitted are designed to provide minimum working clearance between the outer periphery of the torque bars and the inner surfaces of the pockets. This feature reduces the amount of motion or play which the torque bar may undergo during high torque applications.
Therefore, it is a primary object of the present invention to provide an improved cross-bar socket wrench particularly designed for use in working with lug nuts on vehicle wheels, with the wrench of the present invention providing an increased effective working length for the wrench body while preserving a compact configuration for the wrench during storage.
It is a further object of the present invention to provide an improved cross-bar socket wrench which enables the vehicle operator or the mechanic to more effectively remove and re-apply lug nuts when undertaking a vehicle wheel/tire change.
Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawings.